Work holder mechanism



Oct. 3, 1950 Filed Dec. 15, 1947 l. C. MAXWELL EI'AL WORK HOLDER MECHANISM 2 Sheets-Sheet 1 //v VENTORS MA 0. MAXWELL OLE H. LANGEN BY paw-(Wm ATTORNEY:

l. C. MAXWELL EIAL WORK HOLDER MECHANISM 2 Sheets-Sheet 2 Filed Dec. 15, 1947 /M/ENTORE S w m. T A

All.

Patented Oct. 3, 1950 WORK HOLDER MECHANISM Ira C. Maxwell and Ole H. Langen, Minneapolis, Minn., assignors to The Unipress Company, Incorporated, Minneapolis, Minn., a corporation of Minnesota Application December 15, 1947, Serial No. 791,850

7 Claims. 1

This invention relates to work holders for laundry presses and the like having a pressing buck and a presser head movable into and out of pressing engagement therewith; In such pressing machines the garment which is usually in 'a damp condition is laid on the buck and the presser head is engaged for the pressing operation. In the pressing of fiat work such as shirt fronts and backs, it is important to maintain the work flat and free from wrinkles, and to this end various work holders have been devised.

It is an object of the invention to provide an improved workholder which, of course, performs its intended function of holding the work flat and one that is agile in its operation andcapable of moving or being moved quickly to and from its operatingposition. It is also an object to provide an improved work holder which is light in'weight, easily operated, yet strong and positive in action, attractive in appearanace and having good operator acceptance and reasonably automatic in its operation, yet not too complicated.

Other objects of the invention are those inherent in the apparatus herein illustrated, described and claimed.

The invention is illustrated with reference to the drawings in which:

Figure 1 is a partial front elevational view of a pressing machine showing the presser head in engagement with the buck and showing a front elevational view of the work holder of the present invention in work holding positions;

Figure 2 is also a partial front elevational view of the pressing machine of Figure l, but with the presser head raised and the work holder moved to the out-of-the-way position; v

Figure 3 is a fragmentary sectional view of the attachment of the work holder band to one of the bifurcated end pieces of the work holder stem. Figure 3 is taken in the direction of arrows 33 of Figure 2;

Figure 4 is a sectional viewtaken in the direction of arrows 44 of Figure 1 and shows the separated operating mechanism of the work holder;

Figure 5 includes a rear elevational view of the work holder parts in their work-engaging position. In. this view some of the parts of the work holder are broken away and the view is somewhat enlarged. Figure 5 also includes a portion of the presser arm and the air lines and valve and valve operating mechanism.

Figure 6 is a fragmental section taken in the side view of the bifurcated ends on the work holder stem.

Throughout the drawings corresponding numerals refer to the same parts.

Referring to the drawings, the pressing machine includes a main frame l0 supporting the work table II and buck support 12 upon which buck I3 is mounted. Presser arm I4 is pivotally mounted at H: on the rear uprights it (Figure 5) of the main frame and serves to carry the presser head 18 which is thereby moved into and out of engagement with the buck I 3. The press operating mechanism is connected at pivots is and 2|] on the presser arm and are not shown since they, per se, form no part of the invention. Closed press position of'the presser arms M is shown in full lines. Any suitable press operating mechanism may be used.

Upon the main frame member 2! there is mounted the work holder frame casting 22 which is suitably attached to the frame 2| by bolts 24. The work holder frame 22 overhangs the main frame 2! at the right side as shown in'the front View (Figure 1) and carries a pivot shaft 25 that is pivotally mounted in journals 2625 on the work holder frame. In the space between journals 26 and 26 a work holder stem 28 is attached solidly to shaft 25, either by a key, set screw or other suitable device, so that when the stem 28 is moved pivotally in the direction of arrows 30 or 31, shaft 25 is also rotated.

The stem 28 of the work holder assembly extends upwardly and works in a slot 32 in the table H at a position almost immediately under the center line and at on end of the buck l3. At the joint 34 there are solidly attached a bifurcated end of the work holder device, this bifurcated end being composed of a front portion 35 (Figures 1 and 2) and back portion 35 (Figure 5) which extend, respectively, forwardly and rearwardly to positions so as to clear the front and back edges of the buck l3'when the work holder stem and bifurcated end structures 28;i53fi, see Figure 6, which moves as a unit, is swung from the out-of-the-way position of Figure 2 to work engaging position of Figure 1.

To the ends 35 and 36 there are attached a band 38 which is held by bolts 39. At least one end of the band is slotted where the bolts pass through so as to allow the band to move a limited amount endwise in respect to the members 35 and 36. The band 38 is stabilized against flapping by one or-more clips 42 which engage one edge of the band and force it into engagement with a fixed (stabilizing) surface on the end of the member 38, yet the construction permits the band 38 to slide a limited amount.

The frame 22 of the work holder has an end upright 43 which serves as a pivot support at 44 for the base 45 of cylinder 45, which is, therefore, free to oscillate about pivot 44. Cylinder 46 has a piston 41 and piston rod 48, the latter being pivoted at 49 to the stem 28. .Cylinder 45 is vented at 58; hence permits only a limited working stroke on piston rod 48 which is enough to move the work holder against the action of the retaining mechanism 55-4, hereinafter described, and start the stem 28 and the work holder assembly in its arcuate travel in the direction of arrow 38 (Figure 1). Once this occurs the work holder is free moving and continues until stem 28 engages buffer 52 which is mounted on outwardly extending portion 53 of the work holder frame 22.

The retaining mechanism of the work holder includes a lever 54 which is pinned or keyed to shaft 25 so as to move when the work holder 283536 moves. Lever 54 has a side shaft, detent shaft, or projection 55 which carries roller 56 which, therefore, moves in an arcuate path of travel denoted by dotted line 8,

Upon the work holder frame there is an upstanding slotted post 89 upon which the detent lever or plate 6| is pivoted at 62. Lever 8| has a slot 64 in it in which a roller 65 rolls. journal shaft 66 has a spring attached at each end (springs 61 and 68) and these are tensioned as .a pair and attached to eye bolts 19 and TI.

The position of slot 64 in lever B! is such that the roller tends to roll in slot 64 in the direction of arrow I2 when the work holder is brought to the engaging position of Figure land tends to roll in the direction of arrow 14 when lever 6| tilts due to the movement of the Work holder to the position of Figure 2.

The movement of lever 6| is occasioned by the action of roller 59 in entering and moving in an open ended slot 15 in lever 6|. Lever 6| moves to the position shown in Figure 2 and is stopped by the adjustment screw 16 which engages ledge 11 of frame piece 60. The screw 16 may be adjusted so that when springs 61 and 68 pull the lever 6| to the Figure 2 position, the slot '15 of lever 61 will have its center line aligned with the arcuate path of travel of roller 56 on lever 54.

Shaft 25 is also provided with an arm 18 which is pinned or keyed to the shaft 25 so as to move with it. Arm [8 is mounted so that when the work holder mechanism is in the Figure 1 position, the arm 18 will nearly engage the head of adjustable stop screw 19 which is threaded into frame 22. The screw 19 serves to limit movement of the work holder mechanism in the direction of arrow 3|.

Upon the machine frame upright l6 there is mounted a valve 88 which has an operating stem 8| terminating in a flattened top 82 that is lifted in the valve closing direction by spring 84. Air supply line 85 extends through reducer valve 86 and thence via line 87 to the valve 80. From valve 89 a line 88 extends through manual metering control valve 89 and thence via hose 99 to connection 9| on cylinder base 45. On the presser arm or on any other oscillating portion of the pressing machine which moves in unison with the presser head, there is mounted a valve operator having base 92 to which arm 93 is pivoted at 94. The arm 93 is pulled in the direction of arrow 95 by spring ll which is attached to the arm 93 and to base 92. Stop 91 limits this The roller movement. Yet arm 93 can move in the direction of arrow 96 against the action of spring IDI. Arm 93 is provided with a roller 98 pivoted to the arm at pin 99.

Operation-The press may be assumed to be open and the work holder is assumed to be in the position of Figure 2. The press operator then makes the lay of the garment on the buck l3 and after straightening out wrinkles, the operator grasps member 35, which acts as a handle, and swings the entire work holder assembly (28, 35, 36, 38) from the position of Figure 2 in the direction of arrow3l toward the Figure 1 position of the work holder. This movement is free since cylinder 46 is ported and is uninterrupted until roller 56 enters slot 15, whence upon continued movement the lever BI is moved by the action of roller 56 in slot 15 until the springs 61 and 68 are drawn up. Then, as the slot 64 and hence lever 6| is sufficiently tilted, the roller rolls with a quick action from the inner end (Figure 2) to the outer end (Figure 1) and in so doing pulls'the lever 6| in the same direction that roller 56 has up to that time been pushing the lever 6|. Consequently,lever 6| then imposes a holding force onroller 56'and, as shown in Figure 1, the force of springs 61 and 68 which is transmitted'to roller 65 and thence through lever 6| to roller 56 imposes a'torque force on arm 54 tending to move arm 54 and hence the entire work holder in a direction such that the Work holder is held firmly upon the garment. Then the operator closes the press by the usual controls.

In closing the press the roller 98 (Figure 5) which has been-in the dotted line (or open press position) is moved to-the full line position, but valve 89 is not actuated because the roller 98, upon engaging the flat top 82 of the operating stem, simply lifts a slight amount and moves arm 93 in the direction-of arrow 96 against the action of spring 10! which is sufiiciently weak so that it deflects and allows the roller 98 to'move idly over top 82 without imposing on the top 82 a force sufficient to compress spring 84 and open valve 89.

When the pressing operation is completed the operator opens the press by manipulating the appropriate press controls and the presser head lifts and presser arm [-4 moves in the direction of arrow 83 to open press position. In so doing roller 98 moves down along the path of dotted line I65 and engages head 82 and presses valve stem 81 down to open the valve 80, for in this movement-the-lever 93 is held by stop 9! and hence roller 98 operates with determination upon stem 8l82. However, the valve 89 is held open only a short time as the presser arm is moving from closed to open position.

The shot'of air thus injected into line 88 and thence through valve'89 and line to cylinder 46 is moderated by the manual control valve 89 so that the air exerts just sufficient force through piston 41 and piston rod 48, as previously described, to push the work holder stem .28 out of retention by the retaining mechanism (springs 61, 88, roller 84, lever 6|, slot 15androller'56) and then with slight remaining force, flips the work holder stem 28 and members 35, 3B and 38 toward the position shown in Figure 2 where they come to rest against the buffer 52. Port 58 in the cylinder 46 allows the cylinder 46 to exhaust in this position. The movement of the work holder mechanism is very agile and yet is free from abuse to the mechanism itself, the buck of the press or to the operator.

As many apparently widely different embodiments of this invention may be made without departing from the spirit and scope thereof, it is to beunderstood that we do not limit ourselves to the specific embodiments herein except as defined by the appended claims.

What we claim is:

l. A work holder for a pressing machine having a machine frame, a generally horizontal transversely extending buck on th machine frame, said buck having front and back edges, a cooperating presser head, a movably mounted presser arm mounted on said machine frame and carrying said presser head to move the same into and out of pressing engagement with said buck, a pivot shaft mounted on the machine 'frame and extending transversely of the buck below it, a work holder stem extending outwardly from the pivot shaft and having a bifurcated end capable of clearing the front and back edges of the buck as the work holder stem is swung pivotally about the axis of the pivot shaft, a work contacting band attached to the ends of said bifurcated portions, said band being movable thereby into and out of engagement with the buck, an air cylinder having a piston and piston rod therein, said air cylinder and piston rod being connected to the frame and also to said stem and an inlet for air into the cylinder for moving the piston rod outwardly to thereby move ized in that there is included a detent shaft pivotally mounted on said frame and supported be low said transversely extending buck, said detent shaft being parallel to said work holder pivot shaft and adapted to travel through an arcuate path, rigid means interconnecting said mounting for said detent shaft and said work hold-er stem, said detent shaft thereby being operably responsive to movement of said work holder stem for moving said detent shaft through said arcuate path as the stem is swung from a position in which the work holder engages the buck to a position in which the work holder is remote from the buck, lever having a bifurcated end portion pivotally mounted on said frame by pivot means extending parallel to said work holder pivot shaft for movement through a limited arc intersecting said arcuate path of said detent shaft whereby said bifurcated lever may move from a position in which the detent shaft can enter endwise into the bifurcated end portion of said lever and thence arcuately as the detent shaft continues to move, and an over center spring means anchored to said machine frame and connected to said bifurcated lever for urging the continued movement of said bifurcated lever for applying a holding force on the detent shaft and thence upon the work holder stem.

3. The apparatus of claim 2 further characterized in that the detent shaft is carried by a second lever on the pivot shaft.

4. A mechanism of the type described in claim 1 further characterized in that said presser head is carried by presser arms mounted by pivot means to said machine frame, said valve is mounted on said frame below one of said presser arms and has an operating stem located below said presser arm, and said valve operating means consists of a pivoted arm mounted on said presser arm movable to a position such that it does not press the valve stem as the press op erating means moves to close the presser head upon the buck and said pivoted arm is movable to a position such that the operating stem is moved to open the valve momentarily as the press operating means moves to open the press.

5. The apparatus of-claim 1 further characterized in that said work contacting band is slotted at one end forattachmentto one of the bifurcated ends on said work holder stem whereby said band may move a limited amount endwise with respect to said one of the bifurcated ends on said work holder stem.

6. A work'holder for a pressing machine having a machine frame, a generally horizontal transversely extending buck on the machine I frame, said buck having front and back edges, a cooperating presser head, a movably mounted presser arm mounted on said machine frame and carrying said presser head to move the same into and out of pressing engagement with said buck, a pivot shaft mounted on the machine frame and extending transversely of the buck below it, a work holder stem extendin outwardly from the pivot shaft and having a bifurcated end capable of clearing the front and back edges of the buck as the work holder stem is swung pivotally about the axis of the pivot shaft, a work contacting band attached to the ends of said bifurcated portions, said band being movable thereby into and out of engagement with the buck, said apparatus also including a detent shaft pivotally mounted on said frame and supported below said transversely extending buck, said detent shaft being parallel to said work holder shaft and adapted to travel through an arcuate path, rigid means interconnecting said mounting for said detent shaft and said work holder stem, said detent shaft thereby being operably responsive to movement of said work holder stem for moving said detent shaft through an arcuate path as the stem is swung from a position in which the work holder enga s the buck to a position in which the work holder is remote from the buck, a lever having a bifurcated end portion pivotally mounted on said frame by pivot means extending parallel to said work holder pivot shaft for movement through a limited arc intersecting said arcuate path of said detent shaft, whereby said bifurcated lever may move from a position in which the detent shaft can enter endwise into the bifurcated end portion of said lever and thence arcuately as the detent shaft continues to move, and an over center spring means anchored to said machine frame and connected to said bifurcated lever for urging the continued movement of said hifurcated lever for applying a holding force on work table-H and buck support l2 upon which stem.

7. A work holder for a pressin machine having a machine frame, a generally horizontal transversel extending buck on the machine frame, said buck having front and back edges, a cooperating presser head, a movably mounted presser arm mounted on said machine frame and carrying said presser head to move the same into and out of pressing engagement with said buck, a pivot shaft mounted on the machine frame and extending transversely of the buck below it, a work holder stem exwnding outwardly from the pivot shaft and having a bifurcated end capable of clearing the front and back edges of the buck as the work holder stem is swung pivotally about the axis of the pivot shaft, a work contacting band attached to the ends of said bifurcated portions, said band being movable thereby into and out of engagement with the buck, a detent protection spaced from the pivot shaft and connected thereto and to the stem so as to be moved to and fro-through an arcuate path as the work contacting band is moved into and out of engagement with the buck, a detent plate having an cpemended slot therein, a pivot spaced alongside said arcuate path and mounting said plate for pivotal movement intersecting the course of movement of said detent projection, a stop for holding said plate at a limiting position of pivotal movement with the open end of the slot generally aligned with said arcuate path of movement of the detent projection so that said projection can enter the slot When the work holder is moved toward work holding position, the detent plate being thereby moved pivotally by the reaction of the detent projection in said slot, over-center spring means connected to the frame and to said detent plate for resiliently'pivoting said detent plate towards said stop when the plate is pivotally moved to a predetermined intermediate position adjacent said stop and for pivotally urging said detent plate away from the stop when the detent plate is pivotally moved to a predetermined distance away from the stop, said detent plate thereafter being efiective to urge the continued movement of said detent projection and work holder toward work holding position.

IRA C. MAXWELL.

OLE H. LANGEN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,364,196 Davis Dec. 5, 1944 Certificate of Correction Patent No. 2,524,709 October 3, 1950 IRA C. MAXWELL ET AL.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 6, line 63, strike out Work table 11 and buck' support 12 upon which and insert instead the detent shaft and thence upon the work holder;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Office. Signed and sealed this 16th day of January, A. D. 1951.

THOMAS F. MURPHY,

Assistant Uom/mz'saioner of Patents. 

